Physicochemical and Sensory Properties of Ginger Spiced Yoghurt

The physicochemical and sensory properties of ginger spiced yoghurt were investigated in the present study. Four yoghurt samples: A, B, C and D were prepared by addition of 0, 0.5, 1 and 1.5% (W/V) of ginger powder. Physicochemical properties of yoghurt samples determined at day 0 included pH, titratable acidity, dry matter, ash, fat and non-fat solid (NFS). The pH and titratable acidity were also evaluated during 30 days of storage at refrigerated conditions (4 – 6°C). The sensory attributes assessed were colour, odour, taste, texture and overall acceptability. From the results, ginger powder did not affect (P>0.05) the pH and titratable acidity of yoghurt but increased (P≤0.05) the dry matter, fat, NFS and ash content especially when spiced at 1% and 1.5% level. The spiced yoghurt did not show significant changes (P>0.05) in titratable acidityduring storage as opposed to the unspiced yoghurt that increased (P<0.05) with storage time. The pH values of spiced yoghurt were not significantly affected (P>0.05) by storage contrary to the unspiced yoghurt. At the end of storage, the unspiced yoghurt presented the lowest (P≤0.05) pH and the highest (P≤0.05) titratable acidity. Results of sensory evaluation revealed the low appreciation of the spiced yoghurt with an increase in the proportion of ginger powder. However, yoghurt with 0.5% ginger powder was appreciated equally (P>0.05) with the unspiced sample. Spicing yoghurt with ginger powder therefore has positive effect on its physicochemical properties and shelf –life. The yoghurt spiced with 0.5% ginger powder could therefore be recommended.

Plastin 1 widens stereocilia by transforming actin filament packing from hexagonal to liquid

With their essential role in inner-ear function, stereocilia of sensory hair cells demonstrate the importance of cellular actin protrusions. Actin packing in stereocilia is mediated by crosslinkers of the plastin, fascin, and espin families. While mice lacking ESPN (espin) have no vestibular or auditory function, we found that mice that either lacked PLS1 (plastin 1) or had nonfunctional FSCN2 (fascin 2) had reduced inner-ear function, with double-mutant mice most strongly affected. Targeted mass spectrometry indicated that PLS1 was the most abundant crosslinker in vestibular stereocilia, and the second-most-abundant protein overall; ESPN only accounted for ~15% of the total crosslinkers in bundles. Mouse utricle stereocilia lacking PLS1 were shorter and thinner than wild-type stereocilia. Surprisingly, while wild-type stereocilia had random liquid packing of their actin filaments, stereocilia lacking PLS1 had orderly hexagonal packing. While all three crosslinkers are required for stereocilia structure and function, PLS1 biases actin towards liquid packing, which allows stereocilia to grow to a greater diameter

Metabolic Compartmentation – A System Level Property of Muscle Cells: Real Problems of Diffusion in Living Cells

Problems of quantitative investigation of intracellular diffusion and compartmentation of metabolites are analyzed. Principal controversies in recently published analyses of these problems for the living cells are discussed. It is shown that the formal theoretical analysis of diffusion of metabolites based on Fick's equation and using fixed diffusion coefficients for diluted homogenous aqueous solutions, but applied for biological systems in vivo without any comparison with experimental results, may lead to misleading conclusions, which are contradictory to most biological observations. However, if the same theoretical methods are used for analysis of actual experimental data, the apparent diffusion constants obtained are orders of magnitude lower than those in diluted aqueous solutions. Thus, it can be concluded that local restrictions of diffusion of metabolites in a cell are a system-level properties caused by complex structural organization of the cells, macromolecular crowding, cytoskeletal networks and organization of metabolic pathways into multienzyme complexes and metabolons. This results in microcompartmentation of metabolites, their channeling between enzymes and in modular organization of cellular metabolic networks. The perspectives of further studies of these complex intracellular interactions in the framework of Systems Biology are discussed

Yeast Mitochondrial Interactosome Model: Metabolon Membrane Proteins Complex Involved in the Channeling of ADP/ATP

The existence of a mitochondrial interactosome (MI) has been currently well established in mammalian cells but the exact composition of this super-complex is not precisely known, and its organization seems to be different from that in yeast. One major difference is the absence of mitochondrial creatine kinase (MtCK) in yeast, unlike that described in the organization model of MI, especially in cardiac, skeletal muscle and brain cells. The aim of this review is to provide a detailed description of different partner proteins involved in the synergistic ADP/ATP transport across the mitochondrial membranes in the yeast Saccharomyces cerevisiae and to propose a new mitochondrial interactosome model. The ADP/ATP (Aacp) and inorganic phosphate (PiC) carriers as well as the VDAC (or mitochondrial porin) catalyze the import and export of ADP, ATP and Pi across the mitochondrial membranes. Aacp and PiC, which appear to be associated with the ATP synthase, consist of two nanomotors (F0, F1) under specific conditions and form ATP synthasome. Identification and characterization of such a complex were described for the first time by Pedersen and co-workers in 2003

Impact of green tea catechins on the oxidative stability of polyunsaturated fatty acid-rich oils

Lipid oxidation is one of the major causes of deterioration in edible oils, negatively affecting the sensory and nutritional properties of foods and limiting product acceptability. To curb the oxidation of oils during storage and when incorporated into food products, we investigated the effect of green tea catechins on the oxidative stability of oils with a high PUFA content, including DHA-rich oil, linseed oil and sacha inchi oil. The effect of catechins was also evaluated in salad dressings, mayonnaise and crackers enriched with these oils. We showed that green tea extracts (GTEs) enhance the oxidative stability of these oils by limiting the formation of hydroperoxides and their breakdown into secondary oxidation products, decreasing the degradation of fatty acids and inhibiting or reducing the losses in tocopherols. The GTEs were also effective antioxidants in complex food systems enriched with ALA, such as salad dressings and mayonnaise. However, a pro-oxidant effect of GTE was observed in crackers enriched with ALA and DHA, most likely due to the cooking process and interaction of catechins with other compounds in the matrix. In addition, we demonstrated that the antioxidant activity of GTE in the DHA-rich oil was influenced by its catechins profile. GTE rich in epigallocatechin showed more potent antioxidant activity in DHA-rich oil than a GTE rich in epigallocatechin gallate. The efficiency of GTE was also shown to be dose-dependent. Thus, the concentration of catechins in the extract and the quantity of extract added to oil or food products is vital to achieving good antioxidant activity. The results of this research indicate that green tea catechins are suitable for use as natural antioxidants in oils with a high PUFA content.(AGRO - Sciences agronomiques et ingénierie biologique) -- UCL, 202

PESTICIDE EXPOSURE OF BREAD SELLERS AND MICROBIAL SAFETY OF BREAD SOLD IN BAMENDA, CAMEROON

Safety of bread sold in Bamenda municipality has been always problematic because of the poor hygienic practices of sellers. This study aimed at assessing the microbial load of bread sold in Bamenda municipality and pesticides exposure of sellers. Ninety samples of bread were randomly collected from standard bakeries, local bakeries and roadside bread vendors; they were analyzed for total viable count, coliforms and yeast and molds (fungi) using the routine analytical method described by the American Public Health Association. The exposure of some bread vendors to pesticide shops was evaluated using questionnaires. As results, the total viable count ranged from 3.09 x 103 to 2.57 x 105cfu/g, coliform count ranged from 2.27 x 101 to 1.18 x 103cfu/g, while yeast and molds count ranged from 1.32 x 103 to 2.67 x 106cfu/g. Bread from roadside vendors was the most contaminated with molds, while the standard bread was the most contaminated with bacteria and coliforms. The local bread was the least contaminated. Sixteen bread sellers counted around pesticides shops presented ailments (Headache, eye irritation, etc.). Bread sold in Bamenda is contaminated by microbes and some vendors are exposed to pesticides

Evaluation sensorielle du couscous de farine de manioc (Manihot esculenta, Crantz) substituée par celle de patate douce (Ipomoea batatas, Lam)

Consumer Acceptance of Cassava (Manihot esculenta, Crantz) flour's fufu substituted by Sweet Potato (Ipomoea batatas, Lam) Flour. This study investigated the consumer acceptance of fufu made by substituting cassava (Manihot esculenta, Crantz) flour with sweet potato (Ipomoea batatas, Lam) flour at the Food Technology and Post-harvest laboratory of IRAD in Bambui, Cameroon. Four samples of Fufu flour samples F0, F1, F2 and F3 obtained by substituting cassava flour with 0%, 20%, 40% and 50% potato flour respectively were compared. A panel of 30 persons (habitual consumers of Cassava fufu flour) carried out a sensory evaluation of the four samples and gave their level of appreciation with regards to taste, aroma, colour, and texture. The study showed that, the substitution of cassava flour with sweet potato flour had no effect on the aroma of the fufu. The sample containing 20% of sweet potato flour (F1) showed no significant difference in texture and aroma compared (p>0.05) to the control (F0). It was also considered as having the best taste (p<0.05) and was the sample preferred by the panelists. In conclusion, an increase in the proportion of sweet potato flour in the cassava flour had a negative influence on the colour, texture, taste and on the acceptance of the fufu

Green Tea Extract Enhances the Oxidative Stability of DHA-Rich Oil

Docosahexaenoic acid (DHA) is one of the most important omega-3 polyunsaturated fatty acids, with proven health-promoting properties. However, oils with a very high content in DHA (DHAO) are extremely susceptible to oxidation, which affects shelf stability and limits incorporation in food products. Green tea extracts (GTE) are potential candidates for the protection of these oils, but their use in such oils has not been previously reported. This study investigated the effect of GTE (160 ppm, 400 ppm, 1000 ppm) and α-tocopherol (80 ppm, 200 ppm, 500 ppm) on the oxidative stability of a DHAO over a 9-week storage at 30 °C. The oxidative status was monitored during storage by the measurement of peroxide value (PV) and p-anisidine value (p-AV). Changes in eicosapentaenoic acid (EPA) and DHA content, as well as in catechins and tocopherol contents, were also evaluated. The addition of GTE enhanced the oxidative stability of DHAO by reducing the formation of peroxides and secondary oxidation products, whereas α-tocopherol had no significant effect on the PV of oil during storage but led to a significantly higher p-AV. The EPA and DHA content of DHAO was stable in GTE-supplemented samples whereas a decrease was observed in the control and α-tocopherol-supplemented samples. GTE also delayed the degradation of tocopherols initially present in the oil, while catechins resulting from the addition of GTE decreased progressively during the storage perio

The Catechins Profile of Green Tea Extracts Affects the Antioxidant Activity and Degradation of Catechins in DHA-Rich Oil.

This study investigated the effect of the catechins profile on the antioxidant activity of green tea extracts (GTEs) by comparing the antioxidant activity of an EGC-rich GTE (GTE1, catechin content: 58% EGC, 30.1% EGCG, 7.9% EC, and 3.9% ECG) and an EGCG-rich GTE (GTE2, catechin content: 60.6% EGCG, 17.7% EGC, 11.8% ECG, and 9.8% EC) in a DHA-rich oil. The effects of the individual catechins (EGC, EC, EGCG, and ECG) and reconstituted catechins mixtures (CatMix), prepared to contain the same amount of major catechins as in the GTEs, were also measured. All treatments (GTE1, CatMix1, GTE2, CatMix2, EGC250, EC250, EGCG250, and ECG250), each containing epistructured catechins at a concentration of 250 ppm, as well as the control (oil with no added antioxidant), were stored at 30 °C for 21 days with sampling intervals of 7 days. The antioxidant activity was assessed by measuring the peroxide value (PV) and p-anisidine value (p-AV) of oils. Changes in fatty acid content and catechins content were also monitored. Both GTEs enhanced the oxidative stability of the DHA-rich oil, but GTE1 demonstrated a stronger antioxidant activity than GTE2. No significant difference was observed between the PV of treatments with GTE1 and CatMix1 during storage, whereas the PV of oil with GTE2 was significantly higher than that with CatMix2 after 21 days. Among the individual catechins, EGC was the strongest antioxidant. Overall, the antioxidant activities of the extracts and catechins were observed in the decreasing order GTE1 ≈ EGC250 ≈ CatMix1 &gt; GTE2 &gt; EGCG250 ≈ CatMix2 &gt; ECG250 &gt; EC250. A significant change in fatty acid content was observed for the control and EC250 samples, and the catechins were most stable in GTE1-supplemented oil. Our results indicate that the EGC-rich GTE is a more potent antioxidant in DHA-rich oil than the EGCG-rich GTE